Finds study in elderly
A group of chemicals found in commonly used items like nail polish, perfumes and toys could lead to type two diabetes in people older than seventy, a Swedish study has found.
Exposure to these chemicals called phthalates is unavoidable. They are used to make plastic flexible and are also used in perfumes as carriers of fragrance. They can also be found in food packaging, furniture, toys, and in medical devices, such as tubing and intravenous bags.
For the study published in the journal Diabetes Care on April 2, scientists at Uppsala University tested blood samples of a total of 1,016 subjects above the age of 70 for various environmental toxins, including partially metabolised forms of phthalates. To determine whether the participants had prevalent diabetes, the team tested their fasting blood sugar (FBS); 119 subjects were found to have type two diabetes. The researchers found a link between blood levels of some of the phthalates and increased prevalence of diabetes, even after adjusting for factors like obesity, blood lipids, smoking, and exercise habits. High levels of phthalates were shown to double the risk of developing the disease.
“Although our results need to be confirmed in more studies, they do support the hypothesis that certain environmental chemicals can contribute to the development of diabetes," says Monica Lind, lead author and associate professor of environmental medicine at the Section for Occupational and Environmental Medicine in Uppsala University.
The problem with phthalates is that they are used as additives, and can easily escape into air and food. So it is easy to take them in through inhaling, eating and skin contact.
Even though these chemicals do not persist in the human body for a long time, previous research has associated them with a number of health problems like impaired reproduction, obesity, asthma, atherosclerosis, and allergies.
The study describes the possible mechanism by which phthalates could be leading to diabetes risk. PPARs (peroxisome proliferator–activated receptors) are receptors present on cells, helping them to utilise insulin. Phthalates go and bind with these receptors, and interfere with the functioning of glucose metabolism, making it hard for the body to utilise insulin, a hormone that helps cells utilise the sugar we eat and convert it to energy.
Surender Kumar, chairperson of endocrinology and metabolism department of Sir Ganga Ram Hospital in New Delhi says that the results can be extrapolated to the general population as well. “In older people, cells associated with glucose metabolism have slowed down with age, so effects of environment toxins can be more pronounced. However, long-term exposure could affect adults as well.”
He, however, added that the stress caused to the body by such chemicals posed minor risk, compared to some other risk factors like psychological stress.
Ambrish Mithal, chairman of division of endocrinology and diabetes at Medanta the Medicity near Delhi says that this is preliminary evidence and needs to be confirmed through further studies. "It's only a cross-sectional study, the kind that observes the sample at one specific time. To confirm this finding, there is a need of long-term cohort studies wherein you study people with different levels of phthalates over decades."
But the mechanism they've proposed is interesting, he adds. "Some evidence indicates phthalates might be involved in obesity, so there could definitely be a connection here as obesity is a risk factor for diabetes."
In the EU, the US and Japan, certain types of phthalates have been banned in toys, to prevent exposure of kids to these harmful chemicals. India, however, has no regulation for this brand of toxics. Gopal Krishna of non-profit ToxicsWatch Alliance says, "While this study reveals a new health risk from phthalates, other harmful effects like impaired development of reproductory system in infants have been known for long. Despite that there's no policy for regulation of these chemicals in India. There's no mention of them in the Environment Protection Act or Hazardous Waste Rules."
While Bureau of Indian Standards drew standards in line with international norms for use of phthalates in toys last year, they haven't been notified yet. Ravi Agarwal of non-profit Toxics Link, says these standards were mainly to facilitate export of toys. "India lacks any regulation of all chemicals, including phthalates, that come under the category of endocrine disruptors," he says.
He adds there are non-toxic substitutes of phthalates that be used in plastics.
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